blob: 06a27e3f0522b1ff379d10b62f788ccc6e0ee015 [file] [log] [blame]
#!/usr/bin/env python3
# -*- encoding: utf-8 -*-
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
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# software distributed under the License is distributed on an
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# under the License.
''' module for creating streamlets'''
import sets
from heronpy.streamlet.generator import Generator
from heronpy.streamlet.impl.supplierspout import SupplierStreamlet
from heronpy.streamlet.impl.generatorspout import GeneratorStreamlet
class Builder(object):
"""A Builder object is used to build the functional API DAG in Heron."""
def __init__(self):
self._sources = []
def new_source(self, source):
"""Adds a new source to the computation DAG"""
source_streamlet = None
if callable(source):
source_streamlet = SupplierStreamlet(source)
elif isinstance(source, Generator):
source_streamlet = GeneratorStreamlet(source)
raise RuntimeError("Builder's new source has to be either a Generator or a function")
return source_streamlet
# pylint: disable=protected-access
def build(self, bldr):
"""Builds the topology and returns the builder"""
stage_names = sets.Set()
for source in self._sources:
source._build(bldr, stage_names)
for source in self._sources:
if not source._all_built():
raise RuntimeError("Topology cannot be fully built! Are all sources added?")